Voltage rectifier



Sept. 17, 1946. D. R. RASLEY 2,407,724

VOLTAGE RECTIFIER Filed may 29, 1944 INVENTORI DONALD R.RASLEY ATTORNEYPatented Sept. 17, 1946 VOLTAGE RECTIFIER Donald R. Rasley, Fort Wayne,Ind., assignor to Farnsworth Television and Radio Corporation, acorporation of Delaware Application May 29, 1944, Serial No. 537,917

11 Claims.

Thi invention relates to power supply apparatus and particularly toapparatus of this character wherein the supply voltage is divided amonga plurality of loads.

In the operation of multistage electron multipliers it is theconventional practice to derive the accelerating voltages for thesecondary electron emissive multiplier electrodes from a voltage dividerwhich is connected across a source of direct current energy. The voltagewhich is developed in each divider component is dependent upon the totalcurrent fiow in that component. The total current flow consists of thecirculating current through the divider component from the energy sourceand. the electron current flow between the associated multiplierelectrodes where it is desired that the multiplier have a substantiallylinear response, it is necessary that the interelectrode acceleratingvoltages be maintained at substantially constant values. In order toefiect this result the circulating currentthrough the respective voltagedivider components must be considerably greater than the associatedinterelectrode electron current. In this manner fluctuations of theelectron current due to signal variations have little or no effect uponthe voltage drop in the respective divider components. In order toachieve this end with voltage divider consisting of equal impedancecomponents, the components must have rela tively low values ofimpedance.

However, as is Well known in the art, a voltage divider made up entirelyof relatively low impedance components consumes considerable power fromthe source of energy. Inasmuch as the voltage developed in some of thedivider components is not subject to appreciable variation by reason ofvariations of the electron current flow between the associatedmultiplier electrodes, it is not necessary that the impedances of thesedivider components be of relatively small values. Such a condition isparticularly true in the initial multiplier stages where the magnitudeof the electron current flow is comparatively small.

It, therefore, has become the practice to employ a voltage dividerconsisting partly of a group of relatively low impedance components andpartly of a group of relatively high impedance components. One sucharrangement is disclosed in a copending application of Donald R. Rasley,Serial No. 512,541, filed December 2, 1943. The relatively highimpedance divider components are used in association with the lowermultiplier stages where the electron current densities are relativelysmall and the relatively low impedance components are used inassociation with the higher multiplier stages where the electron currentdensities are relatively large. In this manner it is possible to provideaccelerating voltages for the electron multiplier stages which aresubstantially constant, irrespective of fluctuations in the currentdensities representing intelligence signals and at the same time tominimize the consumption of power from the source of energy for thevoltage divider.

Inasmuch as the energy source most conveniently used with apparatus ofthe character described consists of rectified alternating current energyit becomes necessary to adapt such a power supply suitably to provideenergy to a load consisting of both relatively high and low impedanceelements. For certain television applications the unidirectional powersupply also serves as the source of scanning voltage for the deflectorelements. Devices of this character used heretofore have been requiredto deliver energy to only one load.

It, therefore, is an object of the present invention to provide a powersupply for a load circuit consisting of a plurality of impedanceelements.

In accordance with this invention there is provided a source of periodicimpulses from which is to be developed a substantially constantunidirectional voltage. A plurality of energy storage devices areemployed. The energy storage devices are connected to different voltagepoints of the impulse source. There is provided impulse controlled meansfor storing energy in the respective storage devices. There'also isprovided a plurality of circuits connected to the respective storagedevices for dissipating the energy stored therein. Preferably, thedissipation circuits are connected in series.

For a better understanding of the invention, together with other andfurther objects thereof, reference is had to the following description,taken in connection with the accompanying drawing, and its scope will bepointed out in the appended claims.

In the following drawing:

Fig. 1 is a circuit diagram of apparatus en.-

' bodying the invention in one form; and,

source of direct current energy such as a battery I3. The positiveterminal of this battery is connected through the coil I 2 to the tubeanode and. the negative terminal is connected to ground. A coil I 4inductively coupled to the anode coil I2 is connected in series with aresistor I5 between the control grid and cathode of the tube II.

The relatively high voltage terminal of the coil i 2, which is connectedto the anode of the tube II, is coupled by means of a condenser I6 toone terminal of a relatively high impedance element, such as a resistorIT. This resistor is connected in series with a relatively low impedanceelement such as a resistor I8. A relatively low voltage intermediate tapor terminal of the coil I2 is coupled by means of a condenser I9 to thejunction point between the load resistors I1 and I8.

A rectifier tube 2|, having its anode connected to the couplingcondenser I6, is connected in parallel with the high impedance loadresistor I'I. Another rectifier tube 22, having itsanode connected tothe coupling condenser I9, is connected in parallel with the relativelylow impedance load resistor I8.

Referring now to the operation of the apparatus shown in Fig. 1, a briefconsideration will be given to the impulse generator including therelaxation oscillator. The coupling between coils I2 and I4 isregenerative so that, during periods of current increase in the coil I2,the control grid of the tube I I is biased so as to maintain the tubeconducting. Also, during periods of cur rent increase in the coil I2,the anode voltage of the tube is maintained at a substantially constantvalue. At a critical interelectrode voltage the current through the tubeII and the coil I2 ceases to increase and, as a consequence, the controlgrid of the tube becomes negatively biased and current conductionthrough the tube and the coil I2 is interrupted. As a result of therapid decay of current in the coil I2 there is developed at the anode ofthe tube II an impulse of positive polarity and of considerable voltage.At the same time similar impulses are developed in all parts of the coilI2, the voltage thereof being of increasingly lesser magnitude thefarther removed from the anode is the coil portion in which they aredeveloped.

During periods of current increase in the coil I2, when the anodevoltage of the tube I I is being maintained at a substantially constantvalue, the energy stored in the condenser I6 is dissipated through theload resistors I1 and I8. The rate at which this energy is dissipateddepends upon the time constant of the discharge circuit which is afunction of the size of the condenser I6 and also of the value of theload resistors I1 and I8. Inasmuch as the value of the former isconsiderably greater than that of the latter, the effect of the latterupon the dissipation rate is negligible. Similarly, the energy stored inthe condenser I9 is dissipated through the relatively low impedanceresistor I8 during periods of cur-- rent increase in the coil I2. Thisdissipation rate is a function of the value of the condenser I i! andalso of the resistor l8. By properly choosing the time constantdetermining elements of these two circuits the respective rates at whichthe energy stored in the condensers i6 and I9 may be made substantiallyequal.

During periods of current decay in the winding I2 the relatively highvoltage impulses developed at the anode terminal and at the intermediateterminal of the coil render the rectifiers 2| and 22 conducting. In thismanner the energy which ance resistor Il may be associated with thelower multiplier stages and the relatively low impedance I8 may becoupled to the higher multiplier stages. In this manner the circulatingcurrent through the load resistor I! may be maintained at a relativelylow value and the circulating current through the resistor I8 may bemaintained at a sufficiently higher value so that the voltages developedin this resistor are not afiected materially by the interelectrodeelectron currents of substantial magnitudes.

Referring now to Fig. 2 of the drawing, the apparatus embodying theinstant invention is essentially the same as that shown in Fig. 1.Corresponding characters of reference are used in the two figures todesignate similar apparatus. In this modication of the invention theonly essential difierence between that described in connection with Fig.1 is that the rectifier 2| is connected in parallel with both of theload resistors I1 and IB.

There also is no material difference in the mode of operation of theapparatus of Fig. 2 from that of Fig. 1. The dissipation circuits forthe respective condensers I6 and I9 ar the same as those shown inFig. 1. Instead of utilizing only the higher voltage p rtion of theimpulses developed in the coil I2 to restore the energy content of thecondenser I6, in this case the full voltage is utilized. It is believedunnecessary to describe in any greater detail the operation of thismodifi-cation of the invention.

Values of the circuit components of apparatus in accordance with thiinvention necessarily will depend upon the particular requirements ofapparatus of this character. Without intending to limit the invention inany manner, the following table of values of the more important circuitelements is given by way of example for the development from a source ofapproximately 14,000 impulses per second of a power supply to furnish1,500 volts at a current drain of 1 milliampere in a relatively highimpedance load such as the resistor I1 and also 1,000 volts at a currentdrain of 10 milliamperes in a relatively low impedance load uch as theresistor I8.

Condenser l6 .001 microfarad Resistor I'I 2 megohms Resistor l8 0.1megohm Condenser I9 0.02 microfarad Rectifier tube 2I 8016 Rectifier 226H6 While there has been described What, at presout, are considered thepreferred embodiments of the invention, it will be obvious to thoseskilled in the art that various changes and modification may be madetherein without departing from the invention, and therefore, it is aimedin the appended claims to cover all such changes and modifications asfall within the true spirit and scope of the invention.

What is claimed is:

l. A unidirectional power supply comprising, a source of impulses, aplurality of energy storage devices, one of said storage devices beingconnected to a relatively high voltage point of said impulse source andanother of said storage devices being connected to a relatively lowvoltage point of said impulse source, means controlled by said impulsesfor storing energy in said storage devices, and a plurality ofdissipation circuits connected respectively to said energy storagedevices.

2. A unidirectional power supply comprising, a source of impulses, aplurality of energy storage devices, one of said storage device beingconnected to a relatively high voltage point of said impulse source andanother one of said storage devices being connected to a relatively lowvoltage point of said impulse source, means controlled by said impulsesfor storing energy in said storage devices, and a plurality ofdissipation circuits connected respectively to said energy storagedevices, one of said dissipation circuits being of relatively highimpedance and another of said dissipation circuits being of relativelylow impedance.

3. A unidirectional power supply comprising, a source of impulses, afirst energy storage device connected to a relatively high voltage pointof said impulse source, a second energy storage device connected to arelatively low voltage point of said impulse source, means controlled bysaid impulses for charging said energy storage devices, means includinga relatively high impedance circult for dissipating energy stored insaid first storage device, and means including a relatively lowimpedance circuit in series with said relatively high impedance circuitfor dissipating energy stored in said second storage device.

4. A unidirectional power supply comprising, a relaxation oscillatorhaving an output circuit impedance device for the development of aseries of voltage impulses, a first condenser connected to a relativelyhigh voltage point of said output circuit impedance device, a secondcondenser connected to a relatively low voltage point of said outputcircuit impedance device, a pair of rectifiers each connected to one ofsaid condensers and controlled by said impu ses for charging saidcondensers, a relatively high impedance energy issipation circuitconnected to said first condenser, and a relatively low impedance energydissipation circuit connected in series with said relatively highimpedance dissipation circuit and also connected to said secondcondenser.

5. A unidirectional power supply comprising, a relaxation oscillatorhaving connected in the output circuit thereof an inductive Winding forthe development of a series of voltage impulses under the control ofrelatively rapid current changes therein, a first condenser connected toa relatively high voltage point of said inductive winding, a secondcondenser connected to a relatively low voltage point of said inductivewinding, a pair of rectifier tubes, each connected to one of saidcondensers and controlled by said impulses for charging said condensers,an energy dissipation circuit including a relatively high impedanceelement connected to said first condenser, and an energy dissipationcircuit including a relatively low impedance element connected in serieswith said relatively high impedance element and also connected to saidsecond condenser.

6. A unidirectional power supply comprising, a relaxation oscillatorhaving an output circuit for the development of a series of voltageimpulses, a load circuit including a relatively high impedance elementand a relatively low impedance element, a first condenser connectedbetween one terminal of said relatively high impedance element and ahigh voltage portion of said output circuit, a second condenserconnected between one terminal of said relatively low impedance elementand a low voltage portion of said output circuit, means connected inparallel with said relatively high impedance element and controlled bysaid impulses ior charging said first condenser, and means connected inparallel with said relatively low impedance element and controlled bysaid impulses for charging said second condenser.

7. A unidirectional power supply comprising, a relaxation oscillatorhaving an output circuit impedance device for the development of aseries of voltage impulses, a load circuit including a relatively highimpedance element and a relatively low impedance element, a firstrectifier connected in parallel with said relatively high impedanceelement and capacitatively coupled across a high voltage portion of saidoutput circuit impedance device, and a second rectifier connected inparallel with said relatively low impedance element and capacitativelycoupled across a low voltage ortion of said output circuit impedancedevice.

8. A unidirectional power supply comprising, a relaxation oscillatorhaving connected in the output circuit thereof an inductive winding forthe development of a series of voltage impulses under the control ofrelatively rapid current changes therein, a load circuit including theseries connection of a relatively high impedance element and arelatively low impedance element, a first rectifier tube connected inparallel with said relatively high impedance element and capacitativelycoupled across a high voltage portion of said inductive winding, and asecond rectifier tube connected in parallel with said relatively lowimpedance element and capacitatively coupled across a load voltageportion of said inductive winding.

9. A unidirectional power supply comprising, a relaxation oscillatorhaving an output circuit for the development of a series of voltageimpulses, a load circuit including a relatively high impedance elementand a relatively low impedance element, at first condenser connectedbetween one terminal of said relatively high impedance element and ahigh voltage portion of said output circuit, a second condenserconnected between one terminal of said relatively low impedance elementand a low voltage portion of said output circuit, means connected inparallel with both of said impedance elements and controlled by saidimpulses for charging said first condenser, and means connected inparallel with said relatively low impedance element and controlled bysaid impulses for charging said second condenser.

10. A unidirectional power supply comprising, a relaxation oscillatorhaving an output circuit impedance device for the development of aseries of voltage impulses, a load circuit including a relatively highimpedance element and a relatively low impedance element, a firstrectifier connected in parallel with both of said impedance elements andcapacitatively coupled across the terminals of said output circuitimpedance device, and a second rectifier connected in parallel with saidrelatively low impedance element and capacitatively coupled across a lowvoltage portion of said output circuit impedance device.

11, A unidirectional power supply comprising,

a relaxation oscillator having connected in the output circuit thereofan inductive winding for the development of a series of voltage impulsesunder the control of relatively rapid current changes therein, a loadcircuit including the series connection of a relatively high impedanceelement and a relatively low impedance element,

a first rectifier tube connected in parallel with said load circuit andcapacitatively coupled across the terminals of said inductive winding,and a second rectifier tube connected in parallel with said relativelylow impedance element and capacitatively coupled across a low voltageportion of said inductive winding.

DONALD R. RASLEY.

